Process of treating vanadium ores.



-UNITED, STATES PATENT orrion.

' JAMES oTis'HANDY, oF PirT'sBURG, PENNSYLVANIA;

.P o'oEss oF TREATING VANA DlUMQBlES.

Specification of Letters Patent. Application filed June 1906. Serial No. 319,958.

' Patented. Sept.'18., 1906.

ful Improvements in Processes of Treating V nadium Ores; and I do hereby declare the fo lowing to, be "a full, clear, and exactdei tainsto p scription of the invention, such as will enable; others skilled in the art to which it apperactice' and use the same. This' finvention relates to processes of treatin .'vanadiumf ores; and it consists in a Inetho recovering valuable constituents;

fromvanadium; ores, and particularly the; sulfureted ores, in the form of useful pro ducts, all as more fully. hereinafter set forth, mat-y ters lo'f novelty: being particularly pointedj out inthea pended claims:v 72o 1 contain considerable snlfur,-which must bei Sulfurete ores of vanadiumfrequently;

removed'beforeextraction of the vanadium, While the amount-is often greatenough to;

f renderiits recovery desirable, In. a sample} of one such fore. analysis showedapproxi-i mately thirty per cent. of free sulfur, forty per cent of vanadium sulfirl, and thirtyper;

cent.-of-;silicious gangue, From such an ore by the hereinafter-recited method may beg. "HCl. The'temperatur'e at W 'ch thisre'acextracted products corresponding to some; twenty-seven per cent; of vanadium ent-fj oxid or some fifteen er cent. of vana lllIfi.

It is the object oft e-present invention to treat ores of this and like character by a sim;

ple, cheap, and ready method, enablin boththe recovery of the vanadium and of t e sul- I fur, certain. details of the method also being molecular wei ht, an

solubility in water.

applicable to vanadium 'ores' generally.'

Experiment has shown me that compounds "of vanadium contained in ores are readily? converted into pentoxid upon roasting such ores with access of air, especially in the res-' ence of a body'capable of forming avana ate. If this body be a sodium or potassium OOIll-l pound and proper precautionsbe used in. the

treatment, vanadates 'may be formed; ex-

y tained by careful heating with restricted achibiting peculiar relations in regard to'their; Advantage may be' taken of these roperties to prepare merchantable vana ium compounds bya very; simple and directprocess. Sodium com pounds are preferable to those of potassium i or this'purpose, bein cheaper, of lower hence giving less bul masses for treatment and ossessin 7 D solubilities more advantageous. However,

sodium or potassium ma form of any of a number 0 their compounds, vanadiumepentoxid being strongly acid in its nature and readily expelling more volatile acids in roasting. Of the numerous sodium salts of 'vanadic' acid the pyrovanadate is preferable for the present purposes, and it is therefore in general'desirable to use the correct amount. of a sodium compound to form it about four atoms of sodium in Whatever's'alt be employed ,to every'inolecule of vanadium pentoxio.

. Although any sodiumsalt witha -.dis placeable acide suchas sulfate, carbonate, &c.,' or even. the hydrate may be em lo'yed,

achechloridisfbelieved to be the best a a'pted, since at the ordinary roasting temperatures suitablei' zfor forming vanadium pentoxid it vdoes not readily render soluble other substances such as silica, alumina, '&c.and hence comparatively pure solutions may be obtained by directly leaching salt-roasted "ore. Vanadic oxids have a specific-oxidizing influence upon chlorids at roasting temperature in the presence of air, acting as carriers of oxygen, and therefore readily convert potassium compounds may be used. The be used in the sodium or potassium chlorid into vanadates,

the liberatedchlorin escapin as such or as to oxidize the.

In using a method based upon this vanadium in the describe manner, and it is recovery of the sulfur in ores of the class described. For this purpose the ore is prefcess of air. The ore is then roasted to remove the remaining sulfur, the sulfur dioxid formed being available for use in a later ste fur in the formof dioxid, of course all the sulfur may be removed in that form and the ore directly sweet-roasted; but with ores of desirable to combine such removal with the of the process. Where any use exists for su IIO the character described the sulfur is so readily available and in general so purethe ores being frequently'free of arsenicthat it is usually desirable to distil it off in the free form. The removal of the sulfur may be effected I while the ore is in lump form; but it is preferused, maybe directly admixed with the ore during pulverization, as'it serves a good purose 1n the sulfur-expulsion operation 1n eeping'the mass of ore open and unsintered, while remaining inert chemically. In the presence of salt, however, the temperature during sulfur expulsion is preferably kept rather low and as much sulfur as possible driven off as such prior to permitting access of air. The salt, 620., may, however, be admixed after the sulfur expulsion. If carbonate or hydrate of sodiumbe used, the subsequent mixing is better. The amount of salt or other sodium compound is best as previously indicatednot much more than enou h to furnish four atoms of sodium for each mo ecule of vanadium pentoxid. For each pound or part ofvanadium pentoxid resulting from the roasting there may be used a pound'and a uarter or a part and a quarter of common sa tor a corresponding amount of other sodium or potassium salt. In the case of ores containing lead or silver very near the exact amount should be used. Lead chlorid, if formed by an excess of salt, would exercise a detrimental influence later. Withorcs free of lead a slight excess is rather desirable for 35 reasons later appearing. The mixture of sulfur-free ore-and salt is next roasted with free access of air until the color indicates that the oxidation and conversion into vanadate is complete.

The roasted mixture is extracted with hot water, usin" as little as may be necessary for complete so ution of the pyrovanadate. The

concentrated solution so "formed is nearly pure sodium pyrovanadate, containin if the described operations are carefully per ormed, little other dissolved matter except the excess of salt, if such an excess were used. Its purit may be heightened by previously washing the roasted ore with cold water, in which the 'pyrovanadate is little soluble. In the hot-water extraction methodical leaching,.passing the same portion of hot water over successive portions of the roasted ore, is advisable. Washings are used for extracting fresh material.-- The hot-water solution so formed may be treated in a number of ways for the formation of merchantable or useful products. On evaporation to dryness sodium yrovanadate is left in a purity suflicient or commercial purposes, its purity being greater if the roasted ore was first extracted with cold water, as described. Its purity may also be increased by rapidly extractmg the residue after evaporation with cold Water, which removes excess of common 'salt redissolved .in hotwater, &c.

salt and other impurities, leaving behind thepyrovanadate in the form of a commercially pure salt. The presence of the excess of common salt, previously mentioned, is here advantageous, as heightening the insolubility of the pyrovanadate. These differential soluoilities of the pyrovanadate in hot and cold water and the ready formation-of the pyro vanadate by salt-roasting render the above a very suitable method for directly producing a merchantable vanadium compound from any ore, whether sulfureted or not. Vanadate of lead and vanadate of zinc, both com-' mon constituents of vanadium ores, yield readily to this treatment; but in the presence of the former it is desirable to use very little or no excess of salt to prevent the formation of lead chlorid in the leaching, this salt also bein soluble in hotwater and, in-

soluble in c Practicallyihe same result ma be accomplished in another way, also yie ding a pure vanadium compound suitable for var ous purposes. If before evaporating to dryness the solution of the pyrovanadate be decomposed by acidulation with enough of any strong acid to correspond to-its', sodium, the residue-will also be practically pure and may be treated with cold water) in the way described to remove excess of During evaporation and during coolin' much of the vanadic oxid generally crystalli the pentoxi with more or less of the lower oxids. For the acid maybe used the sulfur dioxid evolved in'sulfur expulsion, the chlorin zes out. The nature of the oxid depends upon the particular acid used; but it is generally a mixture of IOO but of course is somewhat richer in vanadium,

and therefore more desirable for many purposes, particularly for furnacing to form ferrovanadium, though the sodium vanadate may also be used for this purpose. When a articularly pure article free from traces o silica, &c., is desired, both treatments may be combined, thesodium pyrovanadate, formed as first described being redissolved, acidu': lated, and the solution evaporated .to .dryness.

' Such vanadium as is dissolved by the cold water in the extractions described may be recovered by acidula'ting and evaporating to dryness, &c.

For-certain purposes the hot-water solution of sodium pyrovana'date maybe precipitated by various reagents to obtain roducts useful for making ferrovanadium, c. Fer rous sulfate yields a mixture of vanadium and iron oxids suitable for this purpose.

Lime or baryta also yield preci itates suitable. These precipitates, as wel as the sodium pyrovanad'ate, the vanadic oxids, or

lIS

the described double treatment is very suit-' able as being free of silica. The sodium pyrovanadate is amenable toitreatment in the furnace without removing the adhering sodium chlorid..

To recapitulate, my process in its present preferred form consists in treating ores of the class described by pulverizing the same with about the proportion of salt specified, expelling and recovering free'sulfur by distillation,

recovering a further portion of sulfur by limited' oxidation, raising the temperature and permitting access of air to burn off residual sulfur, still further raising the temperature tooxidize the vanadium and convert it into sodium vanadate, leaching the roasted ma-j terial with a limited quantity of. hot water to obtain a concentrated solution, evaporating this solution to dryness, extracting the residue fromthe evaporation to removeimpurities and leave a substantially pure vanadate, recovering dissolved vanadium as described, redissolving the vanadate in hot water, acidulating, once more-evaporating, and extracting with cold water. The several steps of this preferred method, however, are all singly useful, and they may be combined in other ways'than that here i'ndicatedf- I dium products from any ore, ,sulfureted or "not.

WhatIclaim i P ,1. The process oftreating sulfureted vana- Jdium ores which consistsin distilling'and re- ";moving'the sulfur from the ore, roasting the treate ore, in admixture with a-s'alt of an alkali metal, and extracting the roasted ore Wi'Q waterII 1 oreswhich 'con sists in distilling and re- "vingthe sulfur from the ore, roasting the reated orein admixture with sodium chlorid e t I F'lhe f treating sulfureted vana- T'treated ore 'ir'i admixture v x i "th -0 W t -hot lterand evaporating the extract to dryness. Q" 4.. The process oftreating sulfuretedvana-v dium ores which consists in distilling and removing the sulfurifrorh-theore, roasting the treatedore in admixture with sodium "chlorid, extracting the roasted ore with hotrwa -ter,evaporating the extract to dryness afid washing the residue with cold water. t

5. The process of treating sulfureted vanadium ores which consists in ulverizin'g said ores,.mixing with sodium ch 'orid, heating to regard my process as particularly applicablev to the production of pure concentrated vana- Theassa es ea -lag aerate-(i al a.

racting the'roastedore withwaterf- -1-i' i t l ire i e, roasting the h sodium chlo-;.

-,-:- '-;12'. The process of distil ofi sulfur,-burning off residual sulfur,

roasting to convert the vanadium into sodium vanadate and extracting with water.

6. The process of treatingsulfureted vanadium ores which consists in pulverizing said ores, mixing with sodium chlorid, heating to distil off sulfur, burning off residual sulfur,

roasting to convert the vanadium into sodium ores which consists in pulverizing said ores, mixing with sodium chlorid, heating: to

distil off sulfur, burning offresidual sulfur,

roasting to convert the vanadium into so dium vanadate, extracting the roasted material with hot water,'evapora'ting the extract to dryness and extracting with cold water.

8. The process of treating sulfureted vanadium ores which consists in pulverizing'said' ores, mixing withsodium chlorid, heating, to distil off sulfur, burning off residual sulfur,

roasting to convert the vanadium into sodium vanadate,'extracting the roasted material with hot water, evaporating the extract to dryness, extractin .with cold water, and re-) a dissolving the resi ue in hot water.

9. The process of treating sulfurete'd vana- I dium ores which consists in pulverizing said ores, mixing with sodium'chlorid, heatingto distil off sulfur, burning ofi residual'sulfur,

roasting to convert vanadium into sodium vanadate, extracting the roasted ,material with hotwater, evaporating the extract to dryness, extracting with cold water, redissolving theresidue in hot water, acidulating and revaporating to dryness.

10. The process of treating. sulfureted vanadium ores whichconsists in pulverizin the same with a quantity of sodium chlori' sufficient to. form sodium pyrovanadate with contained vanadium, expelling and recovering sulfur, roasting to form such pyrovanadate, extracting with hot water and evaporating the'solution to dryness.

vanadi Iii products from vanadium ores which consists 'in' roasting such ores with the proper quantity of alkaline saltsto form pyrovanadate, extracting the "roasted ore to dryness.

with hot waterand evaporating the solution IIO with sodiumchlorid, evaporatingthe solu- 't-ion to drynessand extracting the residue with cold water. I

I '13. The process of preparing high-grade vanadium products from vanadium ores which consists in roasting such ores with the proper uantity of a sodium compound to form so ium pyrovan'adate from contained vanadium, extracting the roasted ore with hot'water and evaporating the solution to dryness.

14. The process of preparing high-grade vanadium products from 'vanadium. ores which consists in roastingsuch ores with a sodium compound, extracting the roasted ore with hot water, evaporating the solution to dryness and extracting with cold water.

15. The process of preparing high-grade vanadium products from vanadium ,oresv which consists in roasting such ores with a sodium compound,- extracting the roasted ore with hot water, evaporating the solution to dryness, extracting with cold water, and redissolving the residue in hot water. i

16. The process of preparing high-grade vanadium products from vanadium ores which consists in roasting such ores with a sodium compound, extracting the. roasted ore with hot water, evaporatin the solution to dryness, extracting with colr water, redissolving in hot water, acidulating and revaporating to dryness.

17 The process of preparing a high-grade vanadium product which consists in acidulating a solution of a crude vanadate of an alkali metal with sufficient acid to saturate the bases present, evaporating and purifying separated solids by extraction of the same with cold water a 18; The process of preparing a high-grade vanadium'product which consists in roasting a vanadium ore with an alkali compound to form a vanadate, preparing a-solution of such vanadate, acidulating the solution, evaporating and purifyin separated solids by washing the same witli cold water.

20. The process of preparing a high-grade vanadium product which consists in roasting a vanadium ore with salt to form a sodium vanadate, preparing a solutionof such vanadate; acidulating the solution, evaporating and purify' g separated solids .by washing the same with cold water.

In testimony whereof I aflix signatin e in the presence of two subscribing witnesses.

- JAMES OTIS HANDY.

Witnesses:

FOSTER HEWETT, JOHN M. BAILEY. 

